We have upgraded the device so that it can be used with batteries installed. Power Supply: 4x1.5V AAA(UM-4)Battery Applications: Whiteness Meter is mainly used to directly measure the whiteness value of object or powder with flat surface. Can be widely used in whiteness measurement of textile printing and dyeing, paint, chemical building materials, paper board, plastic products, white cement, ceramics, enamel, talc powder, starch, flour, salt, detergent, cosmetics and other substances. Features: Also conforms to GB3978, GB3979, GB7973, GB7974, ISO2470, GB8904.2, QB1840, GB2913, GB13025.2, GB1543, ISO2471, GB10339, GB5950, GB12911, GB2409 and other standards. No preheating after starting, measurements can be taken after simple calibration, easy to operate. General Specifications: Range:0~120 Resolution:0.1 Illumination condition:45/0 Illuminant:LED 457 nm Whiteness Formula:Blue Light Whiteness WB=R457 Measuring Aperture:18x11 mm Rectangle Zero Drift:≤0.1 Stability of Display:≤0.5 Repeatability of Measurement:≤0.1 Operating Condition: Temperature:0~40C; Humidity:<85%RH Size:140x45x75 mm Weight:305 g (Including Batteries) Package includes: Main Unit AC Adaptor Standard White Board Optical Cleaning Cotton Cloth Carrying Case Operation Manual